U.S. Pat. No. 4,904,879 describes a data current coupler/assembly, and method of making and assembling the coupler, for receiving signals from conductor wires of a twisted pair of a data bus and transmitting signals therealong. The coupler assembly noninvasively couples the data bus to the conductor wires by using mating pairs of E-shaped electromagnets having windings about central legs of the magnets which are electrically connected to a control unit to sense and transmit signals along the data bus. A lower member, having a cavity to receive conductor wires of the data bus positioned adjacent to the lower electromagnets, is mounted to a panel. An upper member with upper electromagnets includes a circuit substrate having trace windings about substrate apertures, an electronic subassembly to which the windings are electrically connected to amplify transmitted and received signals, and a shielded electrical connector secured at a connector end connected to circuits of the electronic subassembly and matable with a connector of a cable extending to the control unit. The upper member is releasable connected to the upper member via a fastening means and securing means.
U.S. Pat. No. 4,264,827 discloses a method of sensing the transmission of low-level signal current through an electrical conductor without an electrical connection to the conductor, using a continuous closed loop conductor wire extending from a current source with coils of the conductor looped around electromagnet coil articles connected to electronic devices, which arrangement senses changes in the electromagnetic field established by the current. The arrangement can be repeated at a plurality of locations spaced along the conductor with minimal effect to the signal transmission, and can allow signaling of a plurality of electronic devices in response to the signal current passing through the conductor.
Such a current sensing system is desired to be placed aboard aircraft for use with black boxes and other electronic control units, as is disclosed in Proposed ARINC Standard 629 presently being considered by the Airlines Electronic Engineering Committee (AEEC) of Aeronautical Radio, Inc. (ARINC) of Annapolis, Md., and AEEC Letters Nos. 87-094/SAI-309, 87-122/SAI-313, and 88-077/SAI-331, which are incorporated herein by reference. Such a system may also be used in other environments where it is desired that a single closed loop data bus be used.
The couplers above provide important advantages in operation and assembly. Nevertheless, none of these couplers uses an improved electromagnet structure to provide improved coupler performance including an improved conductive wire positioning within the wire channels along with electromagnet insert having sealing means to position and seal the conductor wires to the assembly, improved electromagnetic interference ("EMI") shielding using metallic plating on the upper member rather than a separate shield member, a rugged electromagnet biasing spring means to improve formation of an electromagnet core, a quick action panel mounting means, and improved aligning means to secure the upper member to the lower member.
It is desired to devise an improved noninvasive coupler assembly for sensing and transmitting electrical signals from a twisted pair of a data bus, and a method of assembly of such a coupler assembly, which provides these important advantages.